ECMA Script Interaction With Plasma Shells

It is possible to control and interact with a Plasma user interface shell such as a plasma-desktop or (starting in KDE SC 4.5) plasma-netbook session using ECMA Script (aka JavaScript). This scripting mechanism exposes containments (Desktop Activities and Panels), widgets and various other aspects of plasma-desktop configuration using the widely known and used ECMA Script language. The QtScript engine is used for the runtime environment.

This document describes the API that is provided along with how to
run such scripts in plasma-desktop.

Running Scripts

There are three ways that scripts can be executed in plasma-desktop:

on first run: when plasma-desktop is started without any pre-existing configuration, any scripts in $APPDATA/plasma-desktop/init/ with a ".js" suffix are run. If there is more than one script, they are run sequentially in the alphabetical order of the file names.

Note

For security reasons, scripts located in the user's home directory will not be run during this phase.

on update: when plasma-desktop is started, it will check in

`kde4-config --path data`/plasma-desktop/updates/

with a ".js" suffix for scripts that have not yet been run. If there is more than one script which has not been run yet they will be executed serially in the alphabetical order of the file names.

A record of which update scripts have been run is kept in the application's config file in the [Updates] group. This means that if the plasma-desktop configuraiton file is removed, all the update scripts will be run again.

Note

For security reasons, scripts located in the user's home directory will not be run during this phase.

interactively: an interactive scripting dialog can be requested either via the KRunner window (Alt+F2, by default, or via the "Run Command" entry in various desktop menus) by entering "desktop console" as the search term. It can also be triggered directly via dbus with qdbus org.kde.plasma-desktop /MainApplication showInteractiveConsole

ECMA Script may be entered directly into this window for execution and output appears in the lower half of the window. Ctrl+E is a shortcut to run scripts, and scripts can be saved to and loaded from disk.

Scripts from files can also be loaded using KRunner with "desktop console /path/to/file" or via dbus with

Templates

Templates are a type of Plasma package that contains a script using the Plasma Desktop Scripting API. Templates can be loaded from other scripts by name and may appear elsewhere in the Plasma UI. This allows common elements to be kept as separate scripts which can be referenced from multiple other places as a way to increase consistency and lower maintenance costs.

The use case that triggered the inclusion of this feature was the desire to make it easy for users to re-create the default panel (whatever that might be). There is a Template called org.kde.plasma-desktop.defaultPanel that ships with the KDE Plasma Workspace which contains the layout for the initial default panel. This is referenced by the Plasma Desktop init script and, because it is marked as a Panel Template in the metadata.desktop file it also shows up to the user in the Add Panels menu. When selected by the user from the menu, the exact same panel that is created on desktop start up is created for them, complete with Plasma Widgets and configuration.

A Template is a small set of files in a specified file hierarchy (or, in Plasma terms, a "Package"). In particular, a Template package contains the following files:

metadata.desktop: a .desktop file describing the template

contents/layout.js: a Javascript file containing the actual script

Templates are stored under share/apps/plasma/layout-templates and may be installed using `plasmapkg -t layout_template path/to/package`. Template packages may also be provided as a .zip file with a .plasmalayout suffix.

The metadata.desktop file contains the usual .desktop entries such as Name and Icon but must also contain Type=Service and ServiceTypes=Plasma/LayoutTemplate entries. If the layout is specific to a given Plasma application, such as plasma-desktop, this can be specific using X-Plasma-Shell. X-Plasma-ContainmentCategories defines what kind of layout it is with possible values being panel and desktop. Finally a X-KDE-PluginInfo-Name entry is required to provide a globally unique internal name for the Template. Here is an example of a Template that provides a Panel layout for Plasma Netbook:

When running a template, two global variables will be accesible in read only mode: templateName and templateComment. they will contain the Name and Comment fields of the above desktop file. They will be translated if a localization is available.

API

In addition to the normal ECMA Script API and the Qt-specific extensions (such as signal/slot support) provided by QtScript, the following API is provided for use by scripts.

All of the API below, unless otherwise noted with a version noticed, appear as below in the KDE Software Compilation v4.4.0 and later. API that is not noted as being part of a given class or object is part of the global namespace.

Note

API compatibility is guaranteed from version to version starting with KDE Software Compilation v4.4.0.

Version Numbers

Starting with KDE SC 4.5, the version number of both the scripting API and the application is available to the script via the following read-only properties:

StringapplicationVersion: the version of the application, e.g. 0.3

numberscriptingVersion: the version of the scripting API; e.g. in KDE SC 4.5 this is 2

Activities

Activities are the desktop layer in a plasma-desktop session and may contain widgts. In sightly more technical terms, they are desktop containments. Activities can be created, enumerated, modified and destroyed.

New Activities can be created using the Activity constructor, like this:

var activity = new Activity("folderview")

The string passed into the constructor maps to the X-KDE-PluginInfo-Name= entry
in the plugin's .desktop file). See the documentation on the Containment object class below.

Read-only properties:

Array[number]activityIds: returns a list of integer ids of all existing Plasma activities

Array[String]knownActivityTypes: (scripting version >= 2) a list of types of activities that can be created. This is useful to check if an Activity type is available on the system before trying to construct one.

Functions:

ActivityactivityById(number id): return an object representing the activity with the given id

ActivityactivityForScreen(number screen[, number dekstop]): returns an object representing the activity currently associated with the given screen and, optionally, the given desktop.

Array[Activity]activities(): returns an array of all activities that currently exist

Panels

Panels can be created, enumerated, modified and destroyed. A panel object combines both a containment as well as the container itself, allowing for full control of things such as where it appears on screen and the hiding features associated with them.

New Panels can be created using the Panel constructor, like this:

var panel = new Panel("dock")

The string passed into the constructor maps to the X-KDE-PluginInfo-Name= entry
in the plugin's .desktop file).

Read-only properties:

Array[number]panelIds: returns a list of integer ids of all existing Plasma panels

Array[String]knownPanelTypes: (scripting version >= 2) a list of types of panels that can be created. This is useful to check if a Panel type is available on the system before trying to construct one.

Functions:

PanelpanelById(int id): returns an object representing the Panel that matches the given id

Array[Panels]panels(): returns an array of all panels that currently exist

Activities and Panels

Activity and Panel objects, once created by the script, or as returned by activityById, activityForScreen,
or panelById) provide the following read-only properties:

numberid: the integer id of this activity

StringformFactor: returns the form factor of the activity, e.g. "planar" for most desktop activities,"mediacenter" for media centers and either "horizontal" or "vertical" for panels.

Array[number]widgetIds: a list of integer ids of all the widgets in this Activity

Array[String]configKeys: (scriptingVersion >= 2) a list of all keys that are set in the current configuration group

Array[String]configGroups: (scriptingVersion >= 2) a list of all the groups in the current configuration group

Array[String]globalConfigKeys: (scriptingVersion >= 2) a list of all keys that are set in the current global configuration group

Array[String]globalConfigGroups: (scriptingVersion >= 2) a list of all the groups in the current global configuration group

as well as the following read/write properties:

numberdesktop: the virtual desktop this activity is associated with, or -1 for none

numberscreen: the screen this activity is associated with, or -1 for none

Stringname: the name of this activity

StringwallpaperPlugin: (scriptingVersion >= 2) the wallpaper plugin to use with the Activity

StringwallpaperMode: (scriptingVersion >= 2) the wallpaper plugin mode to use with the Activity

Array[String]currentConfigGroup: (scriptingVersion >= 2) the current configuration group path, with each entry in the array representing a sub-group. This allows one to access trees of groups with code such as: widget.currentConfigGroup = new Array('topGroup', 'subGroupOfTopGroup'). An empty Array means the default (top-level) configuration group for the widget

Stringversion: (scriptingVersion >= 2) the version of the Activity or Panel

and the following methods:

remove(): deletes this activity and all widgets inside of it

WidgetwidgetById(number id): returns an object representing the widget with the given id

WidgetaddWidget(String name): adds a new widget to the activity; the name maps to the X-KDE-PluginInfo-Name= entry

in the widget's .desktop file

WidgetaddWidget(Widget widget): adds an existing widget to this activity; useful for moving widgets between Activities and Panels

showConfigurationInteface(): shows the configuration user interface for this Activity or Panel on the screen

readConfig(String key, any default): (scriptingVersion >= 2) reads the value of key in the config with default for the default value

reloadConfig(): (scriptingVersion >= 2) causes the Activity or Panel to reload its configuration; reaction to configuration changes made using readConfig are usually activated on script exit, but this can be triggered earlier on a per-widget basis using this method

Array[String]currentGlobalConfigGroup: (scriptingVersion >= 2) the current global configuration group path, with each entry in the array representing a sub-group, similar to currentConfigGroup. However, global configuration is shared by all instances of panels and activities of the same type.

Array[Widget]widgets([String type]): (scriptingVersion >= 2) returns all the widgets in the Panel or Activity. If the optional type is specified, only widgets matching that type will be returned.

In addition to all of the above properties and functions, Panel objects also provide the folowing read/write properties:

numberlength: the number of pixels along the screen edge used

numberheight: the height (or for vertical panels, the width) of the panel

Stringhiding: the hiding mode of the panel, one of "none" (for no hiding), "autohide", "windowscover" or "windowsbelow"

Stringalignment: right, left or center alignment of the panel (for vertical panels, right corrsponds to top and left to bottom)

Stringlocation: returns the location of the activity (only relevant for Panels); valid values include "top", "bottom", "left", "right" and "floating"

Widgets

Widgets may be enumerated by calling the widgetIds property on a Activity or Panel object. With a widget id in hand, a Widget object can be retrieved by calling widgetById(id) on an Activity or Panel object. New Widgets can be created with add addWidget(String) function provided by Activity and Panel objects.

A list of all installed widget types can be retrieved the following read-only property:

Array[String]knownWidgetTypes (scripting version >= 2)

A Widget object provides the following read-only properties:

numberid: the id of the widget

Stringtype: the plugin type of this widget

Array[String]configKeys: a list of all keys that are set in the current configuration

Array[String]configGroups: a list of all the groups in the current configuration

Array[String]globalConfigKeys: (scriptingVersion >= 2) a list of all keys that are set in the current global configuration group

Array[String]globalConfigGroups: (scriptingVersion >= 2) a list of all the groups in the current global configuration group

Stringversion: (scriptingVersion >= 2) the version of the Activity or Panel

as well as the following read-write properties:

Array[String]currentConfigGroup: the current configuration group path, with each entry in the array representing a sub-group. This allows one to access trees of groups with code such as: widget.currentConfigGroup = new Array('topGroup', 'subGroupOfTopGroup'). An empty Array means the default (top-level) configuration group for the widget

Array[String]currentGlobalConfigGroup: (scriptingVersion >= 2) the current global configuration group path, with each entry in the array representing a sub-group, similar to currentConfigGroup. However, global configuration is shared by all instances of widgets of the same type.

QRectFgeometry: the geometry of the widget (settable)

StringglobalShortcut: the shortcut sequence (in the format used by QKeySequence, e.g. "Alt+F1") associated with this widget

numberindex: the layout index of the widget; in a Panel this corresponds to the order the widget appears in. Changing the value of the index will change the position of the widget in Panels and may do so in some Activities as well.

and the following methods:

remove(): deletes this widget

readConfig(String key, any default): reads the value of key in the config with default

for the default value

writeConfig(String key, any value): sets key to value in the config

readGlobalConfig(String key, any default): (scriptingVersion >= 2) reads the value of key in the global config with default

reloadConfig(): causes the widget to reload its configuration; reaction to configuration changes made using readConfig are usually activated on script exit, but this can be triggered earlier on a per-widget basis using this method

showConfigurationInteface(): shows the configuration user interface for this widget on the screen

Screen Geometry

Read-only properties:

numberscreenCount: returns the number of screens connected to the computer

Functions:

QRectFscreenGeometry(number screen): returns a rect object representing the geometry of a screen

Misc. Global Properties and Functions

Read-write properties:

boollocked: whether the desktop shell and widgets are locked or not (settable)

Read-only property:

booleanhasBattery: whether or not the system has the ability to run on battery power, e.g. a laptop or mobile device

Functions:

sleep(number ms): sleeps the script for the specified number of millseconds

QRectF

A rectangle class is also provided for use with Widget, Panel and screen geometry properties and functions.

Read-only properites:

booleanempty: true if the rectangle's width or height is less than, or equal to, 0; an empty rectangle is also invalid

booleannull: true if the rectangle has both the width and the height set to 0; a null rectangle is also empty and not valid

booleanvalid: true if the rectangle has a width > 0 and height 0.

Read-write properties:

numberleft

numbertop

numberbottom

numberright

numberheight

numberwidth

numberx

numbery

Constructors:

QRectF

QRectF(number x, number y, number width, number height): Sets the coordinates of the rectangle's top-left corner to (x, y), and its size to the given width and height.

Functions:

adjust(number dx1, number dy1, number dx2, number dy2): adds dx1, dy1, dx2 and dy2 respectively to the existing coordinates of the rectangle

QRectFadjusted(number dx1, number dy1, number dx2, number dy2): returns a new QRectF with dx1, dy1, dx2 and dy2 added respectively to the existing coordinates of the rectangle

translate(number dx, number dy): translates the rect by dx, dy

setCoords(number x1, number y1, number x2, number y2): sets the coordinates of the rectangle's top-left corner to (x1, y1), and the coordinates of its bottom-right corner to (x2, y2).

setRect(number x, number y, number width, number height): sets the coordinates of the rectangle's top-left corner to (x, y), and its size to the given width and height.

booleancontains(number x, number y): returns true if the rect contains the point (x, y)

'moveBottom(number delta): moves the bottom by delta pixels

moveLeft(number delta): moves the left by delta pixels

moveRight(number delta): moves the right by delta pixels

moveTo(number x, number y): moves the top left of the rect to point (x, y)